US President Donald Trump has granted Annapolis mayor Gavin Buckley’s wish to have American flags lowered at half-mast to honour the five employees shot dead at the city’s The Capital newspaper.

Perth-raised Mr Buckley said on Monday his initial request to the White House had been declined.

After outrage began to grow, Mr Trump’s press secretary, Sarah Huckabee Sanders, called Mr Buckley to say flags would be lowered.

“As soon as the president directly heard about the request made by the mayor he asked that we reach out and verify the mayor had made the request and when we did, the president asked the flags be lowered immediately,” Ms Sanders told reporters on Tuesday.

The President quickly issued a proclamation ordering the flags lowered nationwide until sunset on Tuesday.

“Our Nation shares the sorrow of those affected by the shooting at the Capital Gazette newspaper in Annapolis, Maryland,” Mr Trump wrote.

“Americans across the country are united in calling upon God to be with the victims and to bring aid and comfort to their families and friends.

“As a mark of solemn respect for the victims of the terrible act of violence perpetrated on June 28, 2018, by the authority vested in me as president of the United States by the constitution and the laws of the United States of America, I hereby order that the flag of the United States shall be flown at half-staff at the White House and upon all public buildings and grounds, at all military posts and naval stations, and on all naval vessels of the federal government.”

Mr Buckley, elected Annapolis mayor last year, submitted the flag request to the White House over the weekend and said he was disappointed it was not initially approved.

Mr Trump had ordered flags lowered for recent mass-shootings at Florida and Texas high schools and Mr Buckley said the newspaper massacre “was an attack on freedom of speech”.

“It’s just as important as any other tragedy,” Mr Buckley said.

Jarrod Warren Ramos, 38, is accused of walking into The Capital newspaper on Thursday and shooting dead five employees with a shotgun.

-AAP